Spray water design for methanol storage tanks
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Sea friends, is the spray water design for methanol storage tanks based on volume? The 5,000 m3 methanol tank in our plant’s tank area is equipped with spraying water facilities, whereas the 4 tanks with a capacity of 500 m3 each do not have such facilities. Why is that? What is the basis for introducing spray water as well? Is the ambient temperature above 35°C?
OP. In our area, the temperature often exceeds 35°C in summer, but we have never used the cooling spray systems; I think those systems are mainly used to lower temperatures in case of a fire.
We have also designed a spray system to be used in the summer to reduce methanol evaporation! Of course, it can definitely be used for fires as well; generally, methanol storage tanks are equipped with foam systems!
Personal understanding: Methanol has a vapor pressure; at room temperature, its partial pressure is lower than atmospheric pressure, so nitrogen is used to fill the storage tank for nitrogen sealing. Increased temperature and hyperventilation? Release methanol. Some companies may not care about this loss or may reduce minor evaporation by using nitrogen sealing, and therefore do not activate the spray cooling system. In case of a fire, the storage tanks are exposed to intense heat, causing their temperature to rise significantly, which is dangerous; that’s why spray cooling is used. As for the fire in the storage tank itself, it seems that the amount of water from the sprinklers is not sufficient to put out the fire; firefighting efforts are still needed